Supernatural Serum
by Dark-Supernatural-Angel
Summary: When Queen Consolidated is broken into by a man with suspicious strength, CEO Oliver Queen is surprised to find two federal agents on the case. Despite the new enemy in town, the Arrow is more confused by how these two agents seem to know Felicity Smoak. [Different spin on 2x08/2x09 with no Barry Allen] [Crossover with "Supernatural"]. Plz R&R!
1. DAY ONE - Unknown Investigators

"**Supernatural Serum"**

**Disclaimer: **I don't own the characters; those belong to their original creators. The way it's all stringed together is of my making. No profit is being made out of this (*sigh* unfortunately).

* * *

><p><strong>Backstory:<strong>

- Felicity meets the Winchesters in 2012 (reality; 2011-2012 / verse; 2012-2013 aka S7) = S9 (verse; 2015-2016)  
>- Timeline of "Arrow" has been pushed forward by <strong>2 years<strong> (therefore Oliver is shipwrecked in 2009 and saved in 2014) = S2 (2015-2016)

**Ages:**  
>- Dean Winchester (b. 1979)<br>- Sam Winchester (b. 1983)  
>- Oliver Queen (b. 1987, not 1985) = 4 years younger than Sam<br>- Felicity Smoak (b. 1990, not 1988) = 3 years younger than Oliver and 11 years younger than Dean  
>- John Diggle (b. 1979, not 1977) = 8 years older than Oliver and the same age as Dean<br>- Roy Harper (b. 1993, not 1991) = 3 years younger than Felicity and 10 years younger than Sam

***Ages of the "_Arrow_" characters are the same here as they are on the show (it's just the changes in dates that are different)

* * *

><p><strong>REASON why this is listed under "<strong>_**Arrow**_**" only:** because of Felicity.

* * *

><p><strong>TIME <strong>= December 2015 (Winchesters have known Felicity for 3 years)

* * *

><p><strong>Summary: <strong>When Queen Consolidated is broken into by a man with suspicious strength, CEO Oliver Queen is surprised to find two federal agents on the case. Despite the new enemy in town, the Arrow is more confused by how these two agents seem to know Felicity Smoak. [Different spin on 2x08/2x09 with no Barry Allen] [Crossover with "Supernatural"]

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><p><strong>NOTE:<strong> I'm only posting this today to honor Dean Winchester's fictitious birthday.

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><p><strong>*SPN*Arrow*SPN*Arrow*SPN*<strong>

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><p><strong>Chapter 1:<br>DAY ONE - Unknown Investigators  
><strong>

There was a police perimeter set up along one of the warehouses that belonged to Queen Consolidated as they investigated the break in that happened the previous night. Among the investigators was Officer Quentin Lance who was one of the first policemen to arrive at the scene of the crime. And it was an odd crime as the robbery resulted in the metal door of the warehouse being ripped off its hinges. Officer Lance found it to be very peculiar.

Officer Lance and his men weren't the only ones at the scene. Oliver Queen, current co-CEO of Queen Consolidated, was also present to check the latest damage to his family's company. He was accompanied by his executive assistant and his bodyguard, Felicity Smoak and John Diggle, who just so happen to be his most trusted confidants.

Oliver and Diggle were crouched down as they looked over the crushed metal door.

"This door was made of expanded reinforced titanium," Diggle commented before he stood to face Lance, "What did they use to do this?"

Officer Lance shrugged, "Not sure yet. No sign of any explosives." He started to walk around the door with a nervous Felicity falling into step just behind him, "Maybe a crane or a forklift was used. But I'm guessing there were at least three of them, maybe four." His eyes landed on the turned over barrels that were taped off. "And given how quick they got in and out of here, they were fast."

Felicity turned to look at Oliver and Diggle as they joined her. She gave them a questioning look but the men only shook their heads. They were as stumped as she was on the situation.

Unaware of the little exchange, Officer Lance continued to walk further into the warehouse. The trio quickly followed after him.

"Any idea what these guys were so hot to break in here for?" He asked as he tried to spot any disturbances in the warehouses' configuration. It wasn't like the entrance way where there was an obvious sign of a struggle.

The rest of the warehouse was still as organized as ever.

"You didn't happen to leave a spare earthquake machine lying around, did you?" Officer Lance wondered out loud but when he turned around, he was faced with an unimpressed Oliver. Lance cleared his throat, "Sorry."

"This is what we're able to pull off the security cameras." A technician interrupted as he walked up to them.

The quartet turned around and waited for the technician to play the security footage from his tablet.

The footage showed a masked man throw the two guards around as if they weighted nothing until he finally threw a metal container at the security camera, cutting off the feed immediately.

"He was the only guy we got on video," The technician explained once the video ended, "The rest of the crew must have come in after him."

"That is not always the case," a deep voice interrupted from across the warehouse, causing everyone to turn towards the newcomer. With everyone focused on the newcomer, no one noticed the surprise that flickered over the petite woman's face before she masked it behind her glasses.

The newcomer appeared to be a tall thirty-something male with short dirty-blonde hair. He was in a suit and he wasn't alone. A few feet behind him was another male in a suit, a taller one who had shaggy brown hair. His attention had been caught on one of the stations in the warehouse before he quickly moved to rejoin the first man.

"Sorry for the delay." The man continued once he got closer to the original group. "We wanted the coroner's report before we checked out the crime scene." He stopped a few feet away from the others with his partner joining him a few moments later. While the first man didn't have anything else with him, the second one appeared to have a tablet of his own in his hands.

"Great," Lance drawled out, "Who the hell are you?"

The two men reached into the jackets, "I'm Agent Anderson," the first man introduced before he motioned towards the second man, "this is my partner Agent Bolan."

By this time, both of their FBI badges were out and shown towards the group before they put them away again.

"We were just finishing up a case in Central City when we got the call to come down here from our supervisor," Agent Anderson explained with a shrug, "Apparently the unexplained elements of the case caught our boss' attention."

Lance gave the agents a skeptical look, "So you actually think that one guy ripped through this door like it was tin foil?"

"We never truly rule anything out sir. The coroner's report suggests the possibility of one guy doing the damage," Agent Bolan commented as he flipped open his tablet. He tapped a few things into the screen before he turned it towards the group, who all stepped forward to have a closer look.

Everyone could now see a medical photo from the autopsy for one of the guards.

"Do you see the marks on the guard's neck?" Agent Bolan pointed along the peculiar bruise patterns, "The bruising pattern fits only one hand and it takes about 1,250 foot-pounds of torque to break someone's neck."

Oliver paled a bit at the implication, which didn't go unnoticed by Bolan's partner.

"By the looks of it, I'm guessing you don't know how hard it is to break someone's neck." Agent Anderson commented as he stared at Oliver.

Oliver blinked, "Hmm?"

Agent Anderson quirked an eyebrow at him as if goading him to answer which Oliver thought was weird.

Oliver just shook his head at the question, "No. No idea."

"Uh," the technician cleared his throat, causing Oliver and the others to give him their attention. "We're going to need a list of the entire inventory here to figure out exactly what was stolen."

"That would be helpful but I think I already know what was stolen," Agent Bolan interrupted which brought everyone's attention back to him. His partner even gave him a questioning look. "A centrifuge," it was all Bolan said before he turned around and headed back the way he originally came from.

Knowing his partner's antics, Agent Anderson turned and followed after him. What surprised everyone that was left behind was that Felicity didn't hesitate to follow the two suited men. This caused Oliver and the others to follow her.

Once everyone was closing in, Agent Bolan continued his explanation, "My guess is an industrial centrifuge based on the three column base set up that was left behind." He pointed towards the three column base at his feet. The base had misshaped bolts protruding from the concrete. Everyone spread out around the broken base as they looked at the damage.

Before anyone could ask about how Bolan knew about the centrifuge being the missing device, he pointed to a table near the base that they had passed by. "The equipment left behind also suggests that a centrifuge was set up here."

Anderson crouched down to take a closer look at the damage, "Judging by this, the device was just ripped out of the ground like it weighted nothing. They didn't even bother to detach the thing first before taking it."

Curious by the deduction, the technician moved his hands over the computer's mouse which caused the screen to come alive. On the screen was a company log-in for the missing centrifuge. The stunned technician turned around to see the crouching Anderson smirking up at his partner. The technician still wanted to do an inventory check just in case.

Lance frowned, not really seeing the significance of the discovery, "And what exactly is a centrifuge?"

Before Bolan could answer, Felicity beat him to it, "It separates liquids." Everyone's head turned towards her yet her attention was focused on Lance. "The centripetal acceleration causes denser substances to separate out along the radial direction." When she was done,she looked back down at the broken bolts.

With everyone's attention on Felicity, no one noticed the smirk on Anderson's face as he looked at her.

"And the lighter objects move to the top," Bolan added in, bringing all attention back to him.

Felicity smiled, "Precisely." She looked up at the agent, "What did you say your name was again?"

The taller man returned the smile, "Agent Sam Bolan."

"Felicity Smoak."

Oliver blinked at the introduction and looked to his friend, only to see an unfamiliar glint in her eye as she smiled at the agent. He turned to look at the agent only to find the same glint in his eyes. Oliver didn't like it.

As he moved around his partner to stand on the empty side of the broken base, Anderson cleared his throat.

Felicity saw Sam discreetly roll his eyes before she turned to give her attention to his partner.

"It's a pleasure to meet you Miss. Smoak." Anderson spoke once he felt her eyes on him.

Felicity chuckled under her breath, "You too Agent…"

"Dean Anderson," the agent finished for her with a smirk on his face.

Finding the exchange odd, Lance looked towards Oliver only to find that he too had a confused look on his face.

Noticing this, Sam coughed in hopes of bringing his partner's focus back.

Which it did.

Dean cleared his throat and stepped back. "Despite the weight of the device, the cracks in the floor suggest only one guy." He explained as he pointed to the footprint trail that he was standing beside. "Only one set of tracks."

Sam and Dean looked to one another as Oliver crouched down to take a closer look at the base.

"There has to be another explanation," Lance was still skeptical about the one-thief theory.

"If you think like that then you'd never get this solved _sir_," Dean quipped with a smirk, "Sometimes you have to think outside the box."

Lance stared at Dean, like Oliver had done to him earlier, before he pulled Felicity off to the side.

"You might want to fill our mutual friend in on this," Lance whispered to the Arrow's IT girl.

"Don't worry," Felicity gave the older man a tight lipped smile, "I'm sure he's already on it."

Lance nodded, unaware that the vigilante he wanted was already there with him.

When Lance and Felicity moved back towards the broken base, they noticed that they were a man short.

"Where's your partner?" Lance questioned as he looked at the taller agent, who was examining the area around the base a little more thoroughly with Diggle.

Sam looked up, "He went to check where the trail ended."

Lance nodded but it was Felicity that noticed that Sam didn't have his tablet anymore. She gave the agent a questioning look only for him to give her a shrug back as his answer.

Felicity sighed before she moved towards Oliver, "I think we should head back."

Oliver looked up at her.

"You have a few meetings back at the office that you need to attend." Felicity clarified as he straightened himself up, "I couldn't reschedule those."

Oliver nodded, "Its fine Felicity. I don't think we can do much here." He walked up to Lance and requested to be updated on the case's progress before he headed towards the exit with Diggle on his tail.

Felicity sighed as she turned to Sam, "If you need any further help, I'll be happy to assist you Agent Bolan."

Sam chuckled, "We'll keep that in mind Miss. Smoak." He waved towards the exit, "You better get going."

Felicity nodded before her heeled feet scurried her towards the exit. She waved goodbye to Lance as she passed him before she was out of sight.

Lance chuckled to himself. "She's definitely something."

"I'm beginning to see that," Sam agreed yet Lance noticed this hidden glint in the agent's eyes. It was like he knew something that Lance didn't.

Before Lance could question it, they were interrupted by Agent Anderson.

When he got to his partner's side, he did a double take around the area. "Where did the others go?" He was trying to find the petite woman and yet he was coming up empty.

"Mr. Queen was needed back at the office," Sam told his partner before he looked down at the tablet he had given Dean before he left to follow the trail. "Find anything?"

Dean shook his head, "Nope." His grip tightened on the tablet, "I think we're done here."

Sam nodded before he reached into his pocket. He pulled out a card and handed it to Officer Lance, "In case anything new comes up, we can be reached here."

Lance took the card and glanced over Agent Bolan's contact information. "I'll keep that in mind."

The agents said their goodbyes before they headed out towards their 1967 black Chevy Impala. They didn't say anything until they were in the comfort of their car.

Sam turned in his seat and looked at his partner, "Okay, what did you really find?"

Dean rolled his eyes as he flipped open the tablet and tapped a few things onto the screen before he turned it around. "The camera above the door caught the thief in the parking lot. The exit wasn't left in great condition either. It was like a bull had rammed into it or something," he explained as he played the video. When he found the footage, he had it transferred to Sam's tablet before anyone else checked the outside feeds for the thief's escape.

Sam watched the security footage of the thief carrying the centrifuge on its shoulders for a short distance before loading it into a large truck.

"That was definitely not normal." Sam commented as he motioned for the tablet. He wanted to go through it again.

Dean sighed, "That's not all. I didn't find any traces of sulfur when I was following the cracked trail." He ran a hand through his hair, "Sammy, this is looking like nothing we thought it was."

Sam tapped the screen a few times, "Well the EMF meter didn't go off when I was around the base so there is another bust." He sadly added before he tapped the screen again.

"This doesn't make sense. Who the hell would want a centrifuge anyways?" Dean questioned with a groan.

Sam shrugged, "I have no idea but is that a plate?" He asked as he showed Dean the paused image of the thief closing up the truck's door. It was blurry but Dean could make out the outline for a license plate.

"I can't make it out," he looked between Sam and the image, "Do you think you can clean it up?"

Sam frowned, "I can try but she might have to do it."

Dean quirked at eyebrow, "Are we really going to cross that line?"

Sam shrugged, "Well, her boss' company is the one that was hit. It would make sense why we would see her without raising suspicions," he looked back at Dean, "you know for follow-ups with the investigation."

"Alright little brother, set it up," Dean instructed as he turned the Impala on and drove out of the parking lot.

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><p><strong>*SPN*Arrow*SPN*Arrow*SPN*<strong>

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><p><strong>Dialogue Disclaimer: <strong>Any recognizable _Arrow_ dialogue came from 2x08 "The Scientist".

_**Supernatural**_** Aliases:** FBI Agent Anderson was used in 7x02 while FBI Agent Bolan was used in 8x13…both aliases were used by Dean.

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><p><strong>AN #1: **And there you have it! The first chapter of what I hope to be my first multi-chapter SPN/Arrow story! Dean Anderson and Sam Bolan are on the case! So what did you guys think? What do you think will happen next? What parts of Arrow canon will remain and which ones won't? I'd love to hear your guesses!

**A/N #2:** If you love the crossover idea, then check out my collection **"Mysterious Smoak"** for more oneshots set in the Supernatural/Arrow crossover universe!

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><p><strong>Originally Posted: <strong>January 24, 2015


	2. DAY ONE – Afternoon Visit to QC

"**Supernatural Serum"**

**Disclaimer: **I don't own the characters; those belong to their original creators. The way it's all stringed together is of my making. No profit is being made out of this (*sigh* unfortunately).

Manipulations of the cover art/image are mine though.

* * *

><p><strong>Backstory:<strong>

- Felicity meets the Winchesters in 2012 (reality; 2011-2012 / verse; 2012-2013 aka S7) = S9 (verse; 2015-2016)  
>- Timeline of "Arrow" has been pushed forward by <strong>2 years<strong> (therefore Oliver is shipwrecked in 2009 and saved in 2014) = S2 (2015-2016)

* * *

><p><strong>TIME <strong>= December 2015 (Winchesters have known Felicity for 3 years)

* * *

><p><strong>Ages:<strong>  
>- Dean Winchester (b. 1979  36)  
>- Sam Winchester (b. 1983  32)  
>- Oliver Queen (b. 1987  28)  
>- Felicity Smoak (b. 1990  25)  
>- John Diggle (b. 1979  36)  
>- Roy Harper (b. 1993  22)

***Ages of the "_Arrow_" characters are the same here as they are on the show (it's just the changes in dates that are different)

* * *

><p><strong>REASON why this is listed under "<strong>_**Arrow**_**" only:** because of Felicity.

* * *

><p><strong>Summary: <strong>When Queen Consolidated is broken into by a man with suspicious strength, CEO Oliver Queen is surprised to find two federal agents on the case. Despite the new enemy in town, the Arrow is more confused by how these two agents seem to know Felicity Smoak. [Different spin on 2x08/2x09 with no Barry Allen] [Crossover with "Supernatural"]

* * *

><p><strong>NOTE:<strong> Happy Friday the 13th / Happy Early Valentine's Day (Unattached Drifter Christmas)

* * *

><p><strong>*SPN*Arrow*SPN*Arrow*SPN*<strong>

* * *

><p><strong>Chapter 2:<br>DAY ONE – Afternoon Visit to QC**

At Queen Consolidated, Felicity was hard at work. It's been a few hours since she returned to the office with Oliver and Diggle and once they had returned, she only had a few moments to go over any last minute meeting details with Oliver before he was swept up in the business bustle.

While Oliver was busy in the first meeting, Felicity prepared his notes for his second meeting before she was able to get back to her regular executive assistant duties. They were pretty mundane and routine for her taste but she did like the simplicity of it because it allowed her to focus her time on more challenging issues. Originally when she finished her meeting preps, the former IT employee had planned to dig a little deeper into the robbery back at the warehouse. The circumstances of the whole thing really creeped her out…and then to see two FBI agents coming onto the scene, it freaked her out even more.

With everything on the company computer completed, Felicity was ready to execute her plan when an email alert from her tablet caused her fingers to freeze over the keyboard. She gave her bag a curious look before she reached down and grabbed the locked tablet. Once unlocked, Felicity was surprised to find that she had a video attachment with a short email message attached to it.

_**Sorry for crossing the line.  
>We found a possible plate from the parking lot footage.<br>We'll drop by in a little while.**_

_**S & D **_

Felicity sighed as she reread the email. She couldn't be mad at them. She just wished that they had given her more of a head's up before they showed up in her theoretical backyard.

Refusing to think about the complexity any further, Felicity opened the video and watched the thief with wide eyes as he escaped in his getaway car. She could immediately see why they had sent her the video. She tapped a few commands into her tablet before the video was sent into her enhancement program. While that was happening, the video gave her an idea as to where else she could look for possible footage…maybe there was another vantage point of the thief's escape.

When Oliver came back from his first meeting, Felicity had to put her searches on hold to prep him for his next meeting. She never even gave him a chance to ask about any updates for the robbery. She only talked about his second meeting so he complied with her tactics.

Once Felicity returned to her desk, she got back to work on her video search. Even though her focus was on her tablet, she was still able to perform the duties required of her as Oliver's EA when they were required. It was a little different than usual due to one of their warehouses being robbed but she was able to keep all questions to a minimum.

With her attention shifting between her two jobs, she hadn't noticed when Oliver returned to his office.

.*.*.*.*.*.

When Oliver returned to his office after his second meeting, he wasn't surprised to find Felicity huddled over her desk with her eyes glued to the screen while her fingers tapped incessantly over the keyboard. It was a familiar sight for him to see, whether it was at her desk or down in the Foundry, he always found her like that at some point. He was tempted to interrupt her and ask about any updates about the robbery but in the end, he decided against it. He made his way towards his office without disturbing her. Instead of heading to his desk, he detoured to the window that overlooked the city. Oliver thought the current downpour fit his mood perfectly.

He tried to get some work done for the company and yet he found that his mind was elsewhere. So much had happened since he woke up that morning, it still boggled him. There were many times throughout his meetings where his mind had wandered over to that very fact. Just that morning he was welcoming his mother back into the company after she was acquitted only to be told moments later that one of his company's warehouses was robbed the previous night. And the way the robbery occurred, that was another issue entirely. The similarities brought up memories that Oliver wished stayed buried in his past and he feared that they will be unburied sooner than he'd like.

The CEO was brought out of his memories when Diggle called out his name as he walked into the office. Oliver turned from his spot by the window, giving his friend his full attention.

"I got the final inventory from applied sciences," Diggle handed the inventory list to Oliver, who started to look over it, "Agent Bolan was right. The only thing missing is a centrifuge."

Before Oliver could ask anything else, the clicking of Felicity's heels heading their way caught their attentions.

"You have to see this," Felicity greeted as she walked in with her tablet in hand, "I pulled up CC-traffic camera footage from across the street of applied sciences," she stopped in front of them, tapped a few things onto her tablet before she turned it around to show the men, "This is three minutes after the alarm went off."

Oliver and Diggle watched a side view of the thief lifting the centrifuge off his shoulders and into a white truck. Diggle gave Oliver a side glance, hoping to gauge his response to the video, while Oliver's eyes remained glued to the tablet.

Unknown to them, Felicity had shown them the second video she had viewed.

When watching the first video she had received, it got her thinking about possibly getting a closer look to the truck. Originally she had feared that the thief may have destroyed any cameras he spotted like when he first arrived but luckily for Felicity, the thief was too preoccupied with the centrifuge to take notice of the security cameras that he had passed. So while the first video captured a distant view of the thief and his truck, it did provide a possible plate she could work with while the second video captured a closer view of the thief, providing a better look at his appearance, and yet the plate wasn't visible at all. She knew that she should have shown both videos to Oliver and Diggle and yet Felicity decided to hold off on that move.

Before Oliver could ask if that was all that Felicity found, movement out of the corner of his eyes caught his attention. They weren't alone anymore and Diggle noticed that as well.

"Can we help you with something, Agents?" Oliver asked, causing Felicity to turn around and see their new visitors.

Agents Anderson and Bolan walked towards the open office entryway.

"We just have some follow-up questions and evaluations for the investigation, Mr. Queen," Agent Bolan explained with a friendly smile on his face.

Oliver nodded; he kind of expected a follow-up but he thought Officer Lance or someone else from the SCPD would be dropping by, not these foreign agents.

"We won't be a bother," Agent Anderson added as he took a step into the office, "Miss. Smoak actually volunteered her assistance to us so that we don't interrupt your busy schedule." He finished and yet when he noticed that a frown started to form on Oliver's face, the agent couldn't help but smirk.

Luckily for Felicity, neither Oliver nor Diggle saw her roll her eyes at the agent. She was surprised, however, when she felt her elbow being tugged backwards, forcing her to step back a bit and into Oliver's personal space. She turned and gave him a questioning look.

"What are you doing?" Oliver whispered yet she could tell that he was trying to reel himself in and not react to the new intrusions in his life.

"We need to find this intruder. And they seem to know more about it than any of us," she sighed before she looked over her shoulders to glance at the agents. She saw that they were taking in their new surroundings, as if doing so was a way to give them the privacy they needed to talk, "I'd say we need them," she turned and looked up at Oliver, "Wouldn't you?"

Oliver gave a reluctant hum. He hated to admit it but she was right. They needed this intruder to be caught but Oliver feared just how much these agents knew about the situation. What happened if they got too close to the case? Oliver couldn't afford anymore collateral damage on his conscience.

Felicity smiled at the billionaire before she turned and walked towards the agents. "I'll show you around." She walked between them before she led the way outside the office, "Before we get started, would you agents like some coffee? I know this great place just around the corner."

Oliver and Diggle watched as the agents followed Felicity to her desk and waited for her to grab her coat and bag before they followed her out to the elevators. Diggle had to reign in his amusement when he overheard Felicity's coffee offer since she still refused to retrieve coffee for Oliver.

When they couldn't hear her heels anymore, Oliver turned back to look out the window while Diggle turned towards his friend, "Why am I getting the feeling that you know more about this than Felicity's new friends?" Since the warehouse, Diggle had been getting the impression that Oliver was holding something back from them, more so than usual.

Oliver sighed, "Pray that I'm wrong."

The sun continued to glint onto Oliver's face but that didn't stop the thunder to clash in the sun-shower the city was having.

.*.*.*.*.*.

There was silence between Felicity and the agents but that ended once they were alone in the elevator.

"I didn't know you were coming," Felicity spoke while looking forward with her back straight, keeping her professional persona for the cameras inside the elevator. Because of the reflective doors, she could still see the men standing behind her.

Over Felicity's head, Sam and Dean Winchester looked to one another.

"After what happened a few days ago, why wouldn't we be here?" Dean questioned as he looked at her through the reflective surface. After they heard what happened to her, the brothers had agreed that their next stop was going to be Starling City so that they could check up on her for themselves.

Felicity tensed, "I said I was fine." She didn't like to think about it. So much went wrong and it was all because she made the wrong move. No matter how much reassurance that Oliver gave her about it, Felicity knew deep down that she made the wrong move. And that wrong move ended a man's life.

Sam's look at her reflection softened, "You were attacked in this very building Felicity. It's okay if you're not fine.**" **When they got news that Felicity had been taken hostage by Count Vertigo in the very building she worked in, the Winchesters were shocked and furious. They were furious that they couldn't be there for her as well as the fact that they had to learn the news from Kevin Tran (who was actively yet discreetly keeping tabs of what was going on in Starling City for the brothers while doing his own tablet research back at the bunker) instead of from Felicity herself. When they finally got a hold of her, Felicity repeatedly told the brothers that she was fine but Sam and Dean knew that she was shaken and not completely okay; physically maybe but emotionally, not so much. She was supposed to be away from danger and yet it seems to find her no matter where she went.

"One attack isn't going to hold me back," Felicity defended with a sigh, "You still should have told me." It wasn't that she wasn't glad to see them. She just never thought that she would see them while she was at work. She knew they were heading towards the West Coast after they learned about the Count but she never thought she'd run into them like this. They were coming from Hurleyville, New York so she thought she'd have a week or two before they showed up.

Sam bowed his head, "We were just as surprised as you were to see us when we heard the report over the wire." He explained as he thought back to when they heard the police report over Dean's police scanner. They were just outside the city when they first caught wind of it. They would have just ignored it but when they heard about the metal door being ripped apart like it was nothing, they just had to check to see if it was their kind of thing.

"Look on the bright side; at least we're in town for the holidays." Dean quipped in hopes of lightening the mood.

Felicity nibbled on her lower lip, "I'm not ready for them to find out."

Sam and Dean looked to one another again.

"Then they won't," Dean reassured her before he cleared his throat, "Now did you get the footage?"

Felicity nodded but before she could say anything more about it, the elevator opened up to the lobby. She led them out of the building and to the park across the street. She had spotted the black Chevy Impala along the way before she took a seat on a free bench in one of the park's gazebos; it was the perfect cover during a sun-shower. The agents followed her lead and sat on either side of her.

Unperturbed by the seating, Felicity whipped out her tablet and brought up the same video that she had shown Oliver and Diggle.

"I found this before you got here but I did manage to get a plate from the video you sent me." Felicity explained as Sam and Dean watched the video. When it was finished, she brought up the results from the first video. In black and white, Sam and Dean could see the enhanced license plate. Their hope for a lead was dashed with Felicity's next words; "It came back stolen."

Dean groaned, "Figures."

"Who filed the report?" Sam questioned as he took in the details on the tablet's screen.

Felicity tapped the screen a few times, bringing up the police report for the brothers. She held the tablet out so that both brothers could see its contents, "The vehicle belonged to a sugar refinery located two miles from the warehouse. They filed the report a few days ago."

"What are the chances that the thief is using the refinery as his home base?" Sam asked as he tilted the tablet towards him.

Felicity frowned at the thought. "The refinery is still in business. Wouldn't that draw attention to him instead of away from him?"

Dean ran his hand through his hair as he gave his brother's question some thought, "It would make sense though."

Felicity turned towards Dean with a questioning look, leaving the tablet in Sam's hands.

"It would be less suspicious for a company truck to come and go as it pleased as opposed to an unmarked vehicle or one from another company," Dean explained as he looked back at her.

"Have you been able to track it?" Sam asked Felicity as he handed the tablet to Dean to have a look.

Felicity sighed, "I've set up the search for it. Nothing has come up yet. What did you guys come up with?" She looked between the two of them with a hopeful expression. With the weirdness of this case, the only reason she wasn't panicking was because Sam and Dean were there and if they were there, then it meant that they could provide some type of explanation for all the weirdness wrapped around the centrifuge robbery.

Sam nervously scratched the back of his neck, "We're still working on it. Some things aren't adding up here."

Dean hummed in agreement as he passed the tablet back to its owner. Once the device was safely tucked away into her bag, Dean scooted towards Felicity.

"Do you think you can get us into the warehouse again? I don't feel like scaling any fences tonight." He whispered in her ear with a slight teasing tone.

Felicity chuckled, "Are you getting too old for that Dean?"

Dean narrowed his eyes yet there was no real fire behind them, only amusement, "Never."

Sam rolled his eyes as the two ignored him. It wasn't anything new for him but he did like that his brother was enjoying himself again. It was hard not to lighten up when around Felicity.

"If we're going back then we better get going," Sam interrupted before they diverted away from the plan.

Felicity stood up and brushed down her coat before she looked back at the brothers, "Follow me then."

She turned on her heels and walked back towards Queen Consolidated before the brothers got a chance to stand up.

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><p><strong>*SPN*Arrow*SPN*Arrow*SPN*<strong>

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><p><strong>Dialogue Disclaimer: <strong>Any recognizable _Arrow_ dialogue came from 2x08 "The Scientist".

_**Supernatural**_** Places:** Hurleyville, New York is the main location for 9x07 ("Bad Boys"). Therefore this takes place after 9x07.

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><p><strong>AN #1: **And there you have it! Felicity is keeping things from Oliver and the Winchesters have a lead to work on. So what did you guys think? What do you think will happen next? What parts of Arrow canon will remain and which ones won't? I'd love to hear your guesses!

**A/N #2:** You guys are truly amazing readers! I truly didn't expect the response that I got for this story. After the first week, I already had 22 reviews, 1,000 hits, 59 favorites and 122 followers! That just blew my mind away and it's all thanks to you guys! It truly means the world to me to have your support! **THANK YOU!**

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><p><strong>Self-Promotion:<strong> If you love the crossover idea, then check out my collection **"Mysterious Smoak"** for more oneshots set in the Supernatural/Arrow crossover universe!

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><p><strong>Originally Posted: <strong>February 13, 2015


	3. DAY ONE – Latest Developments

"**Supernatural Serum"**

**Disclaimer: **I don't own the characters; those belong to their original creators. The way it's all stringed together is of my making. No profit is being made out of this (*sigh* unfortunately).

Manipulations of the cover art/image are mine though.

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><p><strong>Backstory:<strong>

- Felicity meets the Winchesters in 2012 (reality; 2011-2012 / verse; 2012-2013 aka S7) = S9 (verse; 2015-2016)  
>- Timeline of "Arrow" has been pushed forward by <strong>2 years<strong> (therefore Oliver is shipwrecked in 2009 and saved in 2014) = S2 (2015-2016)

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><p><strong>TIME <strong>= December 2015 (Winchesters have known Felicity for 3 years) / Post SPN 9x07

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><p><strong>Ages:<strong>  
>- Dean Winchester (b. 1979  36)  
>- Sam Winchester (b. 1983  32)  
>- Oliver Queen (b. 1987  28)  
>- Felicity Smoak (b. 1990  25)  
>- John Diggle (b. 1979  36)  
>- Roy Harper (b. 1993  22)

***Ages of the "_Arrow_" characters are the same here as they are on the show (it's just the changes in dates that are different)

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><p><strong>REASON why this is listed under "<strong>_**Arrow**_**" only:** because of Felicity.

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><p><strong>Summary: <strong>When Queen Consolidated is broken into by a man with suspicious strength, CEO Oliver Queen is surprised to find two federal agents on the case. Despite the new enemy in town, the Arrow is more confused by how these two agents seem to know Felicity Smoak. [Different spin on 2x08/2x09 with no Barry Allen] [Crossover with "Supernatural"]

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><p><strong>NOTE:<strong> I'm posting this today in honor of **Jensen Ackles' birthday**, the amazing actor who plays Dean Winchester.

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><p><strong>*SPN*Arrow*SPN*Arrow*SPN*<strong>

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><p><strong>Chapter 3:<br>DAY ONE – Latest Developments**

After some time roaming around the warehouse, Felicity and the Winchesters met back up at the damaged centrifuge base.

"Find anything new?" Felicity asked once Dean returned to her side.

When Dean went to roam the warehouse, Felicity and Sam headed for the security hub. Together they combed through the security feeds but when they came up with nothing, they returned to the rendezvous point. As they waited for Dean, Felicity wanted to see if she could get any information about the stolen centrifuge from the assigned computer terminal Sam had noticed earlier. She was able to use her company ID to log in but there wasn't much useful information on the computer.

Dean shook his head, "There were no EMF signals anywhere so ghost possession is out of the question and there was still no sulfur which cancels our original thought that demons were involved." His part of the recon was to retrace the thief's steps and try to figure out any other paths that first went unnoticed. Throughout his trek, Dean didn't smell any sulfur and he had no readings on his EMF meter. "What about you guys?"

It was Felicity's turn to shake her head yet her attention was still on the computer terminal. She was still trying to sift through the data in hopes of finding something of use to them.

Noticing that Felicity's attention was elsewhere, Sam filled his brother in. "There was no interference in the security feeds so there was no tampering on this end. There was nothing new for us to find here."

Dean groaned at the news, "This just doesn't make sense. It was supposed to be demons."

Felicity stopped and looked over her shoulder, "I thought demons were never supposed to make sense."

Dean waved a dismissive hand at her. He remembered telling her that when they first got to know one another a few years back.

Felicity huffed.

Sam sighed, "Usually but this time their motivations for this don't add up." He walked to stand on the other side of the computer terminal. "Like why would demons go through all this trouble to steal a centrifuge if they could have easily possessed the guards and perform an inside job without sounding the alarms? The guards had no anti-possession markings on them so there wasn't anything stopping a possession from happening." He pointed out as he remembered the coroner's report; the guard had no marks on him aside from the bruising that led to his death.

Felicity nodded along. Sam did have a point. Demons had all sorts of powers that could bring a spotlight onto them or keep them under the radar. If demons wanted to steal something and not bring attention to themselves or to the act itself, they would have just possessed those closest to the thing they wanted to steal. They wouldn't want to risk hunters catching onto their plans but this? This robbery was just asking for attention.

Felicity looked between the brothers, "Could it be something else?"

Sam shrugged, "It's possible…" a whole list of creatures starting reeling through the hunter's mind again but there were still too many variables to consider, "but we're stumped on the idea of why a supernatural entity would want a _centrifuge_ in the first place."

"But why in the world would _anyone_ steal a centrifuge that was guarded by a fortune-500 company?" Dean interrupted as he moved to stand beside Felicity; the very thought bothered Dean, "Supernatural or not, why would anyone want to do that?" He questioned with a raised eyebrow directed at her.

Felicity typed a few things into the terminal before an information page popped up. "The inventory list stated that the missing centrifuge was the Kord Enterprises 2BX-900." She pointed to the screen where the product's code was listed.

Dean scowled, "Like that is supposed to mean something to me. English please Fee."

_He did have a point_, Felicity thought as she skimmed over the information again. Aside from the centrifuge's model, there wasn't anything different about it. It did the same thing that other centrifuges did except that it did it on a bigger scale. Felicity was ready to tell Dean that but Sam beat her to it.

"Centrifuges are meant to separate liquid components from one another," Dean tilted his head towards his brother as he listened; "The industrial size suggests that a lot of liquid separation needs to be done." Sam explained as best as he could for his brother. It wasn't that Dean wasn't smart (his older brother was a damn genius if anyone asked Sam), Dean just didn't bother with learning the technical jargon that had nothing to do with hunting.

Dean blinked as he thought over the explanation, "And that means nothing to me but it definitely doesn't sound good at all."

"Okay, so the question is what would the thief need to separate on a massive scale?" Felicity asked as she typed a few more things into the terminal before another screen popped up. This caused Dean to look over her shoulder to check out the screen while Sam moved around the table to see what had everyone's attention. It turned out that Felicity had found the ingredients that this particular centrifuge was able to process without a problem. She thought that finding the list might help them in some way.

"Is it just me or does this sound less like our kind of case?" Dean questioned as he read through the list; it all seemed like generic materials to him, nothing stood out.

"It wouldn't be if you factored out the super-human strength that appeared on many occasions throughout the robbery." Sam reminded his brother as he skimmed the list. He was able to recognize a few chemicals and drug compounds on the list.

Felicity turned around in her spot so that she could lean her back against the computer terminal. Her hands gripped the terminal's edge as she looked between the brothers. Even with her heels, Felicity still had to look up at them, "But can we really rule out the supernatural? I think the super-strength is a huge deal."

Dean shifted his stance with his side now touching the terminal as his arms crossed over his chest, "Well demons were the top choice of our list but like we said, there were no sulfur residues and there have been no demonic omens in the area."

As Dean spoke, Sam took out their tablet from the inside pocket of his jacket. He quickly turned it on and tapped the screen a few times before he showed the device to Felicity.

She recognized the database immediately as the one that she and Charlie Bradbury (a fellow hacker that the brothers had met a few months after they met Felicity) had created a while back. It listed creatures and their M.O.s in an organized manner. After meeting and hitting it off with one another, Felicity and Charlie both decided that they wanted to do something for the brothers to help them out since they ultimately saved their lives. Once the idea of a database came up between them, there was no stopping the women from following through with it. It took a while for them to complete the program but they had a lot of research to comb through first. They wanted to make sure that they had accurate intel worked into their program. It was only on a trial basis for the duo when Charlie first showed it to the brothers during her first trip to their Bunker headquarters. Felicity hasn't been to the Bunker yet but she has seen it through her web-chats with the brothers.

"A lot of other entities run on their instincts in order to survive but there are very few creatures that have the brains to rob anyone." Sam pointed out as Felicity watched the program list all the possible creatures that could have committed the robbery.

"Shapeshifters could do it," Dean added with a groan when he saw the creature pop up on the tablet's list; again, he was reading the list over her shoulder, "but then again they could have easily taken the spot of a guard and not make it look like a robbery." Dean really hoped that it wasn't a shapeshifter they were dealing with; he hated them with a passion. He didn't just hate them because they had the ability to shift into anyone they wanted. He hated them because ten years ago, one shapeshifter had taken his face and committed a bunch of crimes with it. Because of that shapeshifter, Dean had a murder charge haunting him for quite some time. It made avoiding the authorities all the more crucial for Dean.

Sam shook his head, "The thief was wearing a mask so we couldn't tell if there were camera flare ups or not on his eyes." He pointed out as he thought about their lack of suspicious footage in the security hub. The mask made it impossible to see any distinguishing features on the thief's face.

Felicity looked up at Sam with wide eyes, "I forgot about that." She hadn't been searching for that when she was looking through the security footage; she was more focused on finding his trail than anything else. She had completely forgotten to look for any supernatural elements that a camera could have picked up on.

_I've been spending too much time doing Arrow research, _Felicity silently reprimanded herself before she shook her focus back into place.

She tapped the tablet a few times, allowing the program to continue with its generated list, "What about a vampire? Or a werewolf?"

"You gotta be more specific with werewolves." Dean mumbled as he tapped the werewolf icon on the screen. This caused a branched out portion to occur that had more sub-types of werewolves.

Felicity's eyes widened at the new feature; she hadn't created that portion, "Oh." She looked up at Dean, "Since when has there been more than one type?"

Dean shrugged, "It's a long story."

"That can wait for later." Sam interrupted them, bringing their focus onto him, "Now our guy could be either a vampire or a werewolf, since both creatures have the strength and the robbery did happen at night. So it's a definite possibility."

Felicity looked up at Sam and sighed, "I'm sensing a 'but' to that statement."

The brothers laughed for a little but instead of Sam answering her, it was Dean.

"_But_ what the hell would be the motivation for either creature to steal a damn centrifuge?" All traces of laughter left his face as he mulled over his question. "Vampires want blood while werewolves want human hearts." He clarified with the creatures' most basic needs. There was no need to understand creatures that functioned off their baser instincts. However, it always irked Dean when creatures acted outside their norm; it just complicated things for him and his brother…and now for Felicity too.

"Maybe it's not a supernatural motive but a personal one," Felicity suggested before pursing her lips together in thought. She didn't like the possibility but it was one that they couldn't overlook.

Sam sighed as he rubbed the back of his neck, "That would complicate things."

"So what now?" Instead of taking the lead in regards to research, Felicity left the decision up to the brothers. Because the case had supernatural elements to it, she gave them the lead since they were the experts.

"We keep looking." From his spot by her side, Dean surveyed the empty warehouse floor once again, as if scanning the place would somehow unearth a clue they had missed before, "They always slip up somewhere. We just have to find it."

* * *

><p>Meanwhile in an alleyway just behind Verdant, Sin anxiously awaited alone until she was joined by Roy and Thea. She was surprised to see the latter when she only called the former to meet up with her.<p>

"Sin, you said this was an emergency." Roy said, his version of a greeting, as he approached his friend. He and Thea were meant to have lunch with Moira Queen when he had gotten Sin's text.

Disregarding Roy for a moment, Sin turned to his girlfriend, "No offense, but Thea, you shouldn't be here." It wasn't that Sin didn't like Thea, it was that with Thea there, Sin couldn't openly talk to Roy about her emergency like she had wanted to in the first place.

Thea gave Sin a bemused look, "In the alleyway of the club _I _own?"

Sin raised an eyebrow at the heiress for the claim since everyone knew that the club really belonged to Oliver Queen.

With the look directed at her, Thea crossed her arms over her chest and gave a defying look of her own, challenging the other girl to say something about the club's ownership to her.

Not seeing any budging from Thea after that, Sin sighed. "It's my friend Max. He's missing. I haven't seen him for a week. No one has. Something happened to him." She explained before she looked directly at Roy, "I figured you knew _someone_ who could help." She emphasized in hopes that he understood that she was referring to the Arrow.

Roy started to panic on the inside. He wanted to help Sin out but he sort of made a promise to Thea that he wouldn't go looking for trouble anymore.

"Roy can help you." Thea offered while unaware of Roy's internal panic.

Surprised by the offer, Roy and Sin stared at Thea.

"I thought you wanted me to stay out of trouble," Roy was confused by the turnaround.

Thea shrugged, "I kind of like that you never turn away from someone who needs help." She grinned as she looked at him before she patted his shoulder, "I'll just get someone to cover the club."

Roy frowned, "What do you mean?"

"Oh, I'm coming with you." Thea clarified before she walked off to find one of her employees inside Verdant.

Roy groaned.

"So, we're doing this on our own?" Sin asked with a huff.

"For now," Roy ran a hand over his face, "And I can't exactly ask the Arrow for a favor without any proof to give him. I can't just tell him that a friend is missing without giving him anything to go off of." Roy knew that if he called upon the Arrow with nothing but a name and a suspicion to work on then the Arrow may walk away to deal with bigger problems.

"But you'll ask him?" Sin was feeling a little hopeful at the thought.

Roy nodded.

* * *

><p>The rain had momentarily stopped and the sun had just set when Oliver and Diggle arrived at the warehouse. Oliver's time at the company was done for the day and after having a chat with his mother at lunch (about a company party the next evening to welcome her back), Oliver was free to do his other job without interference. And his first concern was finding the thief that robbed his company.<p>

Unfortunately, Diggle was still focused on Oliver's latest plan for his CEO persona.

"Are you sure this is a good idea Oliver?" Diggle questioned the moment they exited the company car.

Oliver sighed, "I need to get my family back to normal." He didn't like the idea of a party but it was practically expected of the Queen family.

"I understand that but how is throwing a party going to accomplish that?" Diggle just didn't understand how a party would be appropriate. Sure he understood the lavish lifestyle the Queen family lived in but Moira Queen had just been released from prison after being partially responsible for the 503 deaths that occurred during the Undertaking. Who would go to a party to honor her?

"We Queens always throw parties and besides, this one is meant to welcome my mother back into the company." Oliver explained before he opened the door to the warehouse.

Diggle followed closely behind Oliver, "If you say so man." It was clear that Diggle still had his doubts but it was obvious that Oliver was staying firm on the party plan.

They continued their trek to the warehouse's main floor in silence. Everything looked to be in working order once again but Diggle's attention was immediately brought back into focus when Oliver suddenly stopped in front of him. If Diggle hadn't noticed when he did, he would have collided into his friend.

Diggle was about ready to question Oliver for his sudden stop when the billionaire motioned for his friend to be silent and look ahead.

The sight before Diggle was not something he was expecting to see. He quickly looked to Oliver and noticed the tense posture as he continued to stare ahead of him.

From his spot, Diggle could see a few computer terminals turned around and set up around the damaged centrifuge base. It was like a temporary workspace was established.

At one of the terminals was Agent Bolan who seemed to have taken off both his coat and suit jacket, leaving him with his white dress shirt that had the sleeves rolled up to his elbows. This didn't seem out of the norm for Diggle, it was the other agent that surprised him.

A few feet away from the terminal that Agent Bolan was working at stood Agent Anderson. He was leaning against another table that was perpendicular to Bolan's. Like Bolan, Anderson had discarded his coat and suit jacket while his sleeves were rolled up to his elbows. There were a pile of coats just behind Anderson's leaning form yet Diggle was surprised to find Felicity's dark purple coat on top of the pile of black fabric.

Now Agent Anderson's position wasn't what surprised Diggle, it was Felicity's position _beside_ the agent that brought on the emotion.

Like the agents, Felicity had shed her coat, leaving her red dress on display for all to see. Aside from her blonde hair, that dress was actually the most colored thing in the warehouse. Instead of working at the terminal with Agent Bolan, Felicity was tucked closely into Agent Anderson's side, so close in fact that he had one of his arms over her shoulder as both of his hands held a tablet just in front of their faces. If Diggle didn't know any better, he would have thought that both of them were involved in a Skype call or something like that.

But what Diggle found odd was the familiarity between Anderson and Felicity. Because of their close proximity, Diggle thought Felicity would be stiff or tense in her posture (like when strangers get too close to her before she could adjust to their presence) since she just met the agent earlier that day but that wasn't the case. He found no traces of discomfort; all he found was a sense of ease within her stance.

Before he could process what his observations could mean, Oliver was on the move.

"You found something?" Oliver asked a bit more harshly than usual as he approached the makeshift workstation. This caused Sam to turn around from the computer.

Felicity jerked in Dean's arms before she looked to Oliver with wide eyes, "We found something." She quickly turned her eyes away from Oliver and focused them onto her tablet as she rushed to bring a file to the screen.

Diggle noticed that Dean removed his arm around Felicity as he mumbled a few things into his tablet before he tapped the screen. The agent then straightened up and lowered his arm so that his tablet remained by his side before he looked to his partner.

Taking his partner's silent cue, Agent Bolan took charge. "Security footage here managed to capture the thief getting into a vehicle." He paused long enough to give Felicity time to pass her tablet to Oliver so that he could see the footage for himself.

No one missed how she immediately stepped back to Dean's side after passing over her tablet. It basically placed her between the agents.

Once the tablet was in the billionaire's hands, Sam continued, "Felicity was able to clean the footage up enough to pick up the plate number."

While Oliver watched the video, Diggle watched Oliver so he noticed that when the agent said Felicity's name so freely, it caused his friend to tense up even further.

Oliver nodded, "And?"

Dean rolled his eyes; he didn't appreciate the clipped and demanding attitude, "It belonged to a sugar refinery not far from here and it just so happened that they filed a report about their stolen truck a few days ago." He ended with a smug look directed at the billionaire.

Oliver narrowed his eyes a bit at Dean before he focused on Felicity and handed back her tablet, "Can you track the vehicle?"

Felicity sighed; the defeat was evident on her face, "We've been trying."

Before anything else could be said, a mechanical beep resonated throughout the group.

Oliver frowned, "What was that?"

As a unit, Felicity and the agents all looked between the computers and tablets until they came to realize that the beeping alert had originated from Felicity's tablet. With a few swipes on the screen, Felicity's eyes widened when she read the report that had set off her alert system.

"Felicity, what is it?" Dean asked once he noticed that she had a few false starts in regards to sharing the news.

"You're not going to believe this." Felicity looked up from her tablet, "The truck we've been looking for, it was just used to rob a blood bank."

Sam and Dean quickly looked to one another. They both had grim looks on their faces as they tried to figure out what this new development would mean for the case.

"Are you sure?" Oliver had a pensive look on his face when he asked.

Felicity nodded, "Yeah." She tapped a few things into her tablet before she pulled up the police report for the latest robbery, "Our guy just made off with 30,000 CCs of O-negative." Felicity looked worriedly between Sam and Dean.

Diggle sighed; he just couldn't believe these robberies, "What, he has super strength, likes blood? Please don't tell me we suddenly believe in vampires." He quipped but all he got were unimpressed looks, especially from the agents.

Dean stepped closer to Felicity to take a look at her tablet.

Oliver immediately noticed the move and he was surprised to see that Felicity immediately tilted the tablet towards Dean the moment she felt him in her personal space. She did it without him even asking, it was as if they've done the move many times before, so much so that it had become a routine for them. Oliver thought that the observation was odd considering that the agents just arrived to town that day.

"Vampire or not, who the hell needs that much blood and a centrifuge?" Dean cut in (bringing Oliver back to the conversation) as he skimmed the report that she pulled up, "Do they want to mass produce their own line of authentic Bloody Mary cocktails or what?"

Sam ignored his partner's last comment as he tried to work through the facts. "This guy seems to have an agenda. This robbery is more precise in the amount they took and which type it was. They specifically took O-negative and nothing else."

Everyone nodded along in agreement.

"That's the universal blood donor type, right?" Dean asked his partner and when he got a nod, he continued with his input,"Then I'm thinking either a massive transfusion or an O-neg. got very unlucky in an accident."

Felicity cringed,"Neither option sounds good."

"Either way we're missing something." Sam sighed as he pinched the bridge of his nose, "It's not adding up."

Sensing his partner's frustration, Dean took the lead and focused on Felicity. "Is there any way you could pull the security footage from the blood bank from here or do we need to go there to get it?" With his focus on her, he missed the stunned exchange between Oliver and Diggle; neither were aware that the agent knew of Felicity's computer skills since she was introduced as Oliver's EA.

Felicity thought about it for a moment. She knew that she could get the footage if she were in the Foundry but with only her tablet with her at the moment, there was a chance that she couldn't access the footage at that very moment. She was still surprised that her tablet had enough strength to get the blood bank alert that it got.

She started tapping a few things into the tablet, "I could try from here but there is a chance that I would need to go there." She looked up at Dean, "Think you can get me in?"

Dean smirked,"One step at a time."

Oliver blinked as he watched the exchange before him. Something didn't feel right to Oliver…and he was determined to find out.

"Let me know what you find." Oliver grunted out before he turned to walk out. With a public persona to maintain, Diggle quickly followed Oliver out.

Once they were outside, Oliver had a plan in mind.

"I want you to look into these agents." Oliver informed Diggle once their steps were aligned. "There's more to them than they're letting on."

"They seem fine to me." Diggle said as he gave his friend an amused look. While he had his own suspicions about the agents, he had a feeling that they weren't rooted in the same area as Oliver's suspicions.

Oliver stopped at their car and stared at the older man, "Just do it, please." He was not in the mood for any teasing whatsoever. There was just too much on his plate.

Diggle sighed, all joking put aside, "Oliver, when are you going to tell me what exactly we're up against?"

Instead of answering, Oliver got into the car.

.*.*.*.*.*.

"Well that went well." Dean commented after Oliver and Diggle walked out of his sight. He didn't like how the billionaire kept watching him; he had the urge to call him out on it but he knew he couldn't do that without exposing Felicity's connection to them to her _boss_.

Felicity sighed, her grip on her tablet tightened. She couldn't help but feel relieved over the fact that Oliver and Diggle were now gone, the guilt she felt for keeping relevant intel from them was tenfold when she was in their presence. It took a lot out of her to not blab about the intel because she knew that if she did that now then they may ask questions that she can't truly answer right now. For Felicity, it was better for her to keep busy and away from Team Arrow for the time being. Or at least until she figured out how she could share with them what she acquired from the Winchesters.

Felicity closed her eyes, "What now?"

The brothers looked to one another. They noticed her demeanor shift but they didn't press on it. They would wait for her to bring it up when she was ready to.

Instead, Dean started to unroll his sleeves, "We need to find that truck and the blood bank is our only lead." With that said and his sleeves smoothed out along his arms, Dean grabbed his suit jacket and put it on.

"I think I should do that back at the Foundry." Felicity explained with a deep exhale as she powered down her tablet for the moment,"I can be more specific with my searches there. Sadly my tablet can only do so much." She held up the device in question to make her point before she placed it into her bag.

Sam nodded,"Alright. But can you be away from work?" He was worried that her helping them would cause trouble for her at work, which he didn't want. She was the only one out of the three of them that had an actual paying job. The last thing he wanted was to cause Felicity any trouble with her work.

"Being friends with the boss has its benefits sometimes." Felicity dismissed quickly even though she had some worries; Isabel Rochev may be a problem but Oliver wouldn't mind since she was technically solving a crime made against the company.

"Okay then while you do that, we'll head to the blood bank and see if we could follow a trail from there." After suggesting that, Dean gave his brother his coat and suit jacket. Sam wasn't surprised to see that his brother was all ready to go with his own coat on.

"Could Digg be right though?" Felicity nibbled on her lower lip,"Could it be vampires?" She never faced a vampire before but she read the lore and it was nothing like the romanticized versions that Hollywood was spinning them into nowadays.

Sam sighed,"It's looking like it." He quickly unrolled his sleeves and put both of his jackets on,"It wouldn't be the first time that vampires robbed a blood bank before."

Standing by Felicity with her coat now in hand, Dean groaned at the reminder, "Don't remind me." He didn't want to remember that particular vampire case since it resulted in him becoming a vampire only to take a painful cure that thankfully turned him back into his human self.

Felicity gave Dean a sympathetic look as he helped her slip into her coat.

"Sorry." Sam grumbled, not only for bringing up that case but for the guilt he felt with it. Even though he was soulless during that case, with his memories back, Sam still felt guilty for the fact that his soulless-self had used his own brother as vampire bait.

"We better stock up on dead man's blood if vamps are our problem." Dean suggested as he made his way towards his brother, "It's been awhile since we've dealt with vamps."

"We'll deal with that tonight," Sam stated as he turned off the terminal they were using, "Let's just put everything back and then get Felicity back to her car."

Dean nodded and helped his brother rearrange the tables to where they were before with Felicity's guidance.

Once everything was put back into its place, they headed out with a game plan in mind.

Dean drove Felicity back to Queen Consolidated so that she could drive her car to the Foundry while the Winchesters headed to the blood bank to retrieve any more evidence about their thief.

* * *

><p><strong>*SPN*Arrow*SPN*Arrow*SPN*<strong>

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><p><strong>Dialogue Disclaimer: <strong>Any recognizable _Arrow_ dialogue came from 2x08 "The Scientist".

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><p><strong>AN #1: **And there you have it! A little bit more supernatural theories were incorporated so I hope there was no confusion. Jealous!Oliver seems to have made an appearance too. So what did you guys think? What do you think will happen next? What parts of Arrow canon will remain and which ones won't? I'd love to hear your guesses!

**A/N #2:** Once again you guys are truly fantastic! Thank you so much for sticking with me on this! It truly means the world to me to have your support! **THANK YOU!**

**Latest Episode Thoughts: **What did you think of Arrow 3x15? My Olicity heart wasn't pleased yet my Oliver/Diggle brOTP was ecstatic. What did you think of SPN 10x14? While I love Dean vs. Cain, I am now worried for Dean. :( What did you think of either episode?

Both series return with new episodes [Arrow 3x16 & SPN 10x15] on **Wednesday March 18th** (new day for SPN)!

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><p><strong>Self-Promotion:<strong> If you love the crossover idea, then check out my collection **"Mysterious Smoak"** for more oneshots set in the Supernatural/Arrow crossover universe!

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><p><strong>Originally Published:<strong> March 1, 2015


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